JPH04316844A - Preparation of laminated sheet - Google Patents

Abstract

PURPOSE:To prepare an electric laminated sheet reduced in the generation of voids. CONSTITUTION:A layer of a resin 2 wherein chopped strands are mixed with a thermosetting resin is provided between two resin impregnated base materials 1 and the whole is passed through a curing oven 5 to be continuously cured. The resin 2 mixed with chopped strands is defoamed by a defoaming device 3 before lamination.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a laminate suitable for electrical use with few voids.

0002

BACKGROUND OF THE INVENTION With the advancement of semiconductor technology and the development of electronic equipment, the demand for laminates is increasing, and there is a strong demand for higher functionality. Conventionally, this laminate is manufactured by stacking a required number of prepregs obtained by impregnating and drying a fiber base material with a resin, and heating and pressing them to form them. Also, a method is used in which a metal foil is layered on one or both sides of a laminate made of prepregs, and then heated and pressed to form a copper-clad laminate. In addition to this method, there is also a continuous manufacturing method. That is, after a room temperature liquid resin is applied and impregnated onto a continuously conveyed base material, this is further heated and pressed continuously to obtain a laminate. In the above continuous manufacturing process, when making electrical laminates, when the glass fiber base material is impregnated with resin, the more impregnated the glass fiber base material is, the more difficult it is for microvoids to come out during heat and pressure molding, and even after the resin hardens, the voids remain inside the laminate. remain. Due to its voids, it has strong hygroscopic properties and poor electrical properties.

0003

The problem to be solved is to eliminate the cause of void generation when impregnating a glass fiber base material with a resin in the continuous production of laminates. SUMMARY OF THE INVENTION An object of the present invention is to provide a continuous manufacturing method for electrical laminates with less generation of voids.

0004

[Means for Solving the Problems] In order to achieve the above object, the present invention provides continuous production of a laminate in which two elongated resin-impregnated glass fiber substrates are fed in the same direction, overlapped, and heated and pressurized. This is a method for manufacturing a continuous laminate in which a thermosetting resin layer containing chopped strands which has been degassed in advance is provided between the two resin-impregnated glass fiber substrates and then heated and press-molded. The content ratio of chopped strands to thermosetting resin is 5
Effective when ~25%. The chopped strands used have a diameter of 6 to 13 μm and a length of 3 to 25 mm. If the diameter, length, and content are less than the above, the reinforcing effect of the chopped strands will be weak; if the diameter, length, and content are more than the above, the restoring force of the chopped strands in the resin will be strong, making it easy to trap air when applying the resin. This may cause voids. Regarding the defoaming of the chopped strand-containing resin, there are methods such as a reduced pressure method and a centrifugal separation method, but the method is not limited as long as defoaming is possible. The thermosetting resin used in the present invention can be generally applied to phenol resins, epoxy resins, unsaturated polyester resins, diallyl phthalate resins, unsaturated acrylic resins, vinyl ester resins, etc. In addition, the fillers added to the resin include aluminum hydroxide, clay, talc,
Wollastonite, antimony trioxide, antimony pentoxide or mixtures thereof can be used. The base material impregnated with the above resin is a glass fiber woven fabric or non-woven fabric,
There are kiss methods, reverse methods, etc. for resin impregnation, but any method that allows sufficient impregnation may be used.

[0005]

According to the present invention, since the core layer of the laminate is degassed in advance, there are no causes of void generation, and the causes of void generation in the surface layer of the laminate can be sufficiently dealt with by conventional techniques.

[0006]

EXAMPLE The production of a metal foil-clad laminate used in an example of the present invention will be explained with reference to FIG. 1, which shows a side view of an example of the apparatus. A thermosetting resin mixed with chopped strands was degassed under reduced pressure using a deaerator 3 and then applied between two continuously conveyed resin-impregnated substrates 1 . The two sheets of the resin-impregnated base material 1 are stacked together using a roll 8, and copper foil 4 is further stacked on both sides, and then passed through a curing furnace 5 and cut with a cutting machine 6 to form a copper-clad laminate 7.
I got it. Furthermore, the materials used in this example will be explained. Unsaturated polyester resin (Hitachi Chemical Polyset PS-1
740) BPO per 100 parts by weight (hereinafter referred to as parts)
A glass cloth is impregnated with a resin to which 2 parts of paste (50% benzoyl peroxide) is added to form a resin-impregnated base material 1, and between the two sheets, 102 parts of the above resin is mixed with 15 chopped strands.
After adding and stirring 50 parts of aluminum hydroxide, 50To
A resin obtained by defoaming under reduced pressure at rr for 15 minutes was applied. Next, copper foil with a thickness of 35 μm was layered on both sides, passed through a curing furnace 5 at 100° C. for 25 minutes without pressure, and cut into a 500×500
A copper-clad laminate with a thickness of 1.5 mm was obtained.

[0007] As a comparative example to compare with the example, the following was carried out. The procedure was the same as in the example except that two sheets of glass paper (weighing 75 g/m2) impregnated with the same thermosetting resin compound as used in the example were used instead of the thermosetting resin compound mixed with chopped strands. A copper-clad laminate of 500 x 500 mm was obtained.

The number of voids after etching the copper foil surface of the double-sided copper-clad laminates obtained in Examples and Comparative Examples was measured. The results are shown in Table 1.

[0009]

[Table 1]

0010

According to the present invention, as is clear from the values shown in Examples and Comparative Examples in Table 1, it has been confirmed that a laminate suitable for electrical use can be obtained in which the number of voids generated is significantly small.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the manufacturing method of the present invention.

[Explanation of symbols]

1 Resin-impregnated base material 2
Thermosetting resin containing chopped strands 3 Defoamer
4 Copper foil 5 Hardening furnace
6 Cutting machine 7 Copper-clad laminate

Claims (2)

[Claims] Claim 1: In the continuous production of a laminate in which two elongated resin-impregnated glass fiber substrates are fed in the same direction and overlapped and then heated and pressurized, the gap between the two resin-impregnated glass fiber substrates is degassed in advance. A method for manufacturing a laminate, comprising providing a thermosetting resin layer containing chopped strands and performing heating and pressure molding. 2. The method for producing a laminate according to claim 1, wherein the chopped strand content of the chopped strand-containing thermosetting resin is 5 to 25%.